1. Field of the Invention
The invention relates to an electrical connector, more particularly to an electrical connector having terminals terminated to twisted pairs of wires.
2. Description of the Related Art
In order to ensure good performance of high data transmission connectors with twisted pair cabling, test methods are provided to measure the transmission characteristics of connectors, such as connector attenuation and cross-talk.
Attenuation is a measure of signal power loss through a cable and connector at various frequencies, and is derived from swept frequency voltage measurements on short lengths of twisted pair test leads, such as 100 ohm and other impedances. The lower the attenuation value, the better the attenuation performance.
Crosstalk is a measure of signal coupling from one pair to another within a connector at various frequencies. The lower the crosstalk value, the better the crosstalk performance.
From tests of the aforesaid transmission characteristics, it is noted that the performance of a twisted pair connector is greatly improved when the twists of the paired wires are maintained as close as possible to the point of termination where the exposed conductors of the wires are terminated to the respective terminals.
FIGS. 1, 2 and 3 show a typical cable connector which includes two rows of terminals 11 installed within a connector housing 10 for electrical connection with a cable 12. The cable 12 has a portion of shielding 13 which is cut off to expose a plurality of pairs of wires 14. The paired wires 14 are originally twisted within the sheathing 13 and are untwisted into individuals so as to be positioned to two adhesive tapes 15 in an order corresponding to that of the respective terminals 11 which are aligned in two rows. Each pair of wires 14 are separated and are respectively attached to the two adhesive tapes 15, and each adhesive tape 15 is folded into two layers to sandwich the wires 14 as best shown in FIG. 3. The wires 14 attached to the upper adhesive tape 15 are soldered to the respective terminals 11 in the upper row, whereas the wires 14 attached to the lower adhesive tape 15 are soldered to the respective terminals 11 in the lower row. Since the paired wires 14 are untwisted for a considerable length before reaching the point of termination, a crosstalk problem is observed when the transmission characteristics of this cable connector are tested. It is desirable to minimize the crosstalk problem encountered with such a cable connector.